There is a critical gap in the knowledge on how to implement effective interventions for renal transplant recipients (RTRs) to improve immunosuppressant therapy (IST) adherence and clinical outcomes. The objectives of this project were to address this gap through: (1) designing, implementing, and evaluating a patient-specific behavioral contract intervention to improve RTRs' IST adherence rates (contracts are written, signed agreements between the RTR and healthcare provider in which the RTR agrees to be adherent to IST according to mutually agreed upon criteria); and (2) measuring the effects of IST adherence on RTRs' health-related quality of life (HQoL) and healthcare utilizations and costs. The primary hypothesis was that at one year post trial enrollment, RTRs who establish behavioral contracts with healthcare professionals will be more adherent than those who do not establish behavioral contracts and subsequently will have greater HQoL and lower healthcare utilizations and costs. Once it is better understood how to implement effective IST adherence intervention programs, clinicians will have a valuable tool to promote therapeutic success, improve HQoL, and reduce healthcare utilizations and costs. Therefore, we pursued the following Specific Aims: (1) determine the effectiveness of an IST adherence contract-based intervention on IST adherence; (2) determine the relationship between IST adherence, the intervention, and RTRs' HQoL; and (3) determine the influence of IST adherence and the intervention on RTRs' healthcare utilizations/costs. To achieve the Specific Aims, a randomized controlled trial of the patient-specific behavioral contract-based intervention was conducted, and data regarding adherence, HQoL, and healthcare utilizations/costs were collected over a 12-month period for each RTR study participant and analyzed. This project will promote healthy lives, increase well-being, and reduce burden of illness and disparity among adult RTRs by providing data regarding an adherence intervention and the impact of IST adherence and the behavioral contract intervention on RTRs' health and economic outcomes and HQoL. Collectively, this new knowledge will provide critical steps toward optimizing RTRs' graft maintenance, productivity, and HQoL, while decreasing graft rejection, return to dialysis, morbidity, mortality, and healthcare costs.